This invention relates to a method of managing the activation or booting of a computer system and a virtual computer system, or in particular, to a technique for suppressing the activation of the computer.
The virtualization technique for concentrating a plurality of jobs on a single computer improves the utilization efficiency of the hardware resources such as the processor, the memory and the input and output units on the one hand and can change the resource assignment in accordance with the processing amount on the other hand.
A configuration in which a plurality of computers are activated by reading the operating system (OS) from the same storage volume, on the other hand, can change the computer for executing a job. The configuration of a storage unit that can be shared by a plurality of computers is called a storage area network (SAN), in which the storage unit and the computers are connected through a fiber channel switch or a storage switch.
In the storage unit that can be shared, the storage volume can be accessed or updated from all the computers connected, and therefore, the problem of security has been posed. To overcome this problem, the storage unit sets a specified computer in correspondence with the storage volume in the storage unit using a world wide name (WWN) as unique device identification information stored in a host bus adapter (HBA) making up an I/O adapter of the fiber channel (FC) held by the computer.
This function of setting in correspondence is called a host group, and by use of the host group, the right of access to the storage volume is granted only to a computer having the HBA with the WWN thereof registered in the storage volume.
In the case where a plurality of computers are prepared to execute a job, either the WWN of the computer executing the job is registered anew in the host group each time the computer is switched, or the WWNs of the plurality of the computers are registered in the host group beforehand. The WWN is registered anew each time of switching the computer at the sacrifice of a bothersome operation.
The advance registration of the WWNs of a plurality of computers in the host group, on the other hand, makes it possible for the plurality of the computers to access the same storage volume, and therefore, fails to solve the security problem.
In view of this, U.S. Pat. No. 7,321,927 discloses a management server which simplifies the operation by eliminating the need of changing the setting in the host group. According to this method, the WWN is transferred to that of the new computer to which the computer executing the job is changed. A plurality of WWNs assignable to a plurality of computers and the storage area identification information are stored in correspondence with each other in the management server in advance, and a WWN and the corresponding storage area identification information are sent from the management server to the computer executing the job. The computer executing the job sets the WWN and is booted from the area indicated by the storage area identification information.
In the case where these computers are virtual computers, a virtualization mechanism defines a virtual I/O adapter to store unique virtual device identification information. U.S. Published Application No. 2006/0195617 discloses a system in which the unique virtual device identification information is set in the I/O adapter of the virtual computer using the technique by which a plurality of device identification information can be registered in the I/O adapter of a computer. With this system, the WWN registered in the host group of the storage unit can be rendered to coincide with the WWN of the virtual I/O adapter of the virtual computer, and therefore, only a specified virtual computer can access the storage volume.
Conventionally, in the case where the computer executing the job is switched from a virtual computer to a (physical) computer or to a virtual computer on a different computer, the registration change or the multiple registration in the host group is avoided by transferring the device identification information set in the I/O adapter to that of the computer to which the computer executing the job is switched.
In this system, assume that it becomes impossible to use the management server, the operation is interfered with by other than the management server, or an application occurs in which the same device identification information would be originally set in a plurality of computers. In such a case, a plurality of computers may come to have the same device identification information.
Once a plurality of computers having the same device identification information are activated, the problem is posed that the access control mechanism of the storage unit fails to work effectively, with the result that a plurality of computers can undesirably access the same storage volume. Also, in the case where the I/O adapter is a network interface, a communication error may be caused if a plurality of computers have the same network device identification information such as a MAC address.